Assembly and test of a prototype nEXO charge-readout module with built-in, cryogenic ASIC readout*

The nEXO experiment aims to discover neutrinoless double beta decay of xenon 136, with a lifetime sensitivity goal of greater than 10^28 years. Compared to using long cables to transmit signals outside of the detector, mounting amplification and digitization circuitry directly on detector submodules reduces noise and improves measurement fidelity. A cryogenic application specific integrated circuit (ASIC) called CRYO ASIC has been designed by SLAC and fabricated for direct attachment to the nEXO charge readout modules. In this talk, the electrical characteristics of the nEXO charge readout will be discussed along with ASIC performance considerations. A prototype nEXO charge-readout module with attached ASIC has been assembled and operated in a liquid xenon time projection chamber; this module’s performance using a full chain of ASIC-controlling circuit boards will be presented.